In a known manner, the fan provided at the upstream end of a turbojet comprises blades carried by a rotor disk, with platforms arranged between the blades and fastened by radial flanges to flanges of the disk by means of threaded rods inserted through bushes mounted in orifices in the flanges of the platform and through flanges of the disk, these platforms making it possible to guide the air stream entering the turbomachine and to avoid unwanted air flows toward the disk.
During the operation of the turbomachine, the breaking of the connection between a blade and the disk can result in the destruction of the adjoining platform. Specifically, the blade then comes up against the lateral edges of the platform and/or against the flanges of the platform, thereby producing a considerable stress on the fastenings used to fasten the platform flanges to the disk flanges and possibly causing these fastenings to break and the platform to be ejected into the air flow path, and resulting in the destruction of parts of the turbomachine that are located downstream.
To overcome this problem, it has been proposed to form deformable regions on the lateral edges of the platform. Another solution, which may, if appropriate, be used in combination with the preceding one, is to form abutment regions on the flanges of the disk to prevent contact between the platform and the blade. Hence, the stress is no longer borne by the platform but by the flange of the disk. However, these solutions are not satisfactory since they do not impart any flexibility to the connection between the flanges of the platform and the flanges of the disk and do not allow sufficient absorption of the energy due to the impact between the blade and the platform.